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The ivory-billed woodpecker (Campephilus principalis), long suspected to be extinct, has been rediscovered in the Big Woods region of eastern Arkansas. Visual encounters during 2004 and 2005, and analysis of a video clip from April 2004, confirm the existence of at least one male. Acoustic signatures consistent with Campephilus display drums also have been(More)
Maternity and paternity uncertainty represent important costs to breeders among white-fronted bee-eaters (Merops bullockoides) in Kenya. Analysis of enzyme polymorphisms reveals that between 9% and 12% of all offspring are genetically unrelated to one or both of their putative parents. These ‘bastards’ are the result of three different sources of parental(More)
White-fronted bee-eaters (Merops bullockoides) are cooperative breeders in which half of all nesting attempts are assisted by non-breeding adults in addition to the breeding pair. These “helpers” assist in all aspects of nesting and their aid significantly increases fledging success. The social unit in these bee-eaters is an extended family clan in which(More)
In the tropical forests of Central and South America, army ants of the Eci-tonini tribe, and the numerous animals that follow them through the understory, share a complex relationship that has far-reaching effects on population dynamics and community structure. Although considerable study has been made of various participants in this relationship , no(More)
•We studied sexual size dimorphism, intrasexual competition, and sexual selection in an individually marked population of Wattled Jacanas (Jacana jacana) in the Republic of Panama. Males are the sole incubators of eggs (28-day incubation) and primary providers of chick care (50-60 days). Females were 48% heavier than, and behaviorally dominant over, males.(More)
Jacanas represent the extreme in avian sex-role reversal. We studied the division of labour between the two sexes in parental care of the eggs and chicks in wattled jacanas, Jacana jacana, in the Republic of Panama. Males were the sole incubators of the eggs (515 clutches). Males were also the sole caretakers of chicks for 97% of broods (NZ 252). Caretaking(More)
Most evaluations of the effects of human activities on wild animals have focused on estimating changes in abundance and distribution of threatened species; however, ecosystem disturbances also affect aspects of animal behavior such as short-term movement, activity budgets, and reproduction. It may take a long time for changes in behavior to manifest as(More)
Individual identification of the relatively cryptic forest elephant (Loxodonta cyclotis) at forest clearings currently provides the highest quality monitoring data on this ecologically important but increasingly threatened species. Here we present baseline data from the first 20 years of an individually based study of this species, conducted at the Dzanga(More)
Considerable controversy exists over the question of the importance of kin selection in the maintenance of helping behaviors among birds. We examined nine different hypotheses of how helpers might benefit from engaging in alloparental care activities. We break these into four categories: Through its activities the helper may A) improve its probability of(More)
Foraging theory predicts that dietary niche breadth should expand as resource availability decreases. However, Galápagos marine iguanas often die during algae shortages (El Niños) although land plants abound where they rest and reproduce. On Seymour Norte island, a subpopulation of iguanas exhibited unique foraging behavior: they consistently included the(More)